Surrey Fire and Rescue Service sent 15 crews to Strawson Hall, Albert Road, after it was called at 1.06am.
Surrey Police has upped its patrols in the area and appealed for witnesses after it was emerged the fire was started deliberately.
Investigating officer Detective Sergeant Oana King said: “We understand that this fire will cause concern among the community but I would like to reassure you that we will do all we can to bring the person responsible to justice.
“We have increased our patrols in the area as a result and are engaging with the community regarding relevant crime prevention advice.
“This happened on a Sunday night when it would have been quiet on the streets and so anybody in the area would have been more out of place.
“If you saw anybody acting suspiciously, either on foot or in a vehicle in the Albert Road area then please get in touch with us immediately.
“Likewise if you know of anybody who came in late smelling of smoke or acting suspiciously then we would like to hear from you.
“If you don’t want to talk to us then you can disclose any information anonymously to the independent charity Crimestoppers by calling 0800 555 111.”
Anyone with any information should call Surrey Police on 101 or report it online at https://my.surrey.police.uk/splonlinereportingweb quoting the reference number 45150041114.